Effect of carbon monoxide on the carbothermal reduction and nitridation reaction of alumina

The carbothermal reduction and nitridation (CRN) of alumina (Al2O3) to aluminum nitride (AlN) were investigated under a flow of mixed gas of nitrogen and carbon monoxide (CO). The powders obtained by calcining the (hydroxo)(succinato)Al(III) complex under a flow of the mixed gas with different CO contents were characterized by powder XRD and 27Al magic-angle spinning (MAS) NMR spectroscopy. The complex decomposed into ρ-Al2O3, which was then converted into either AlN or δ-Al2O3 through γ-Al2O3, depending on the CO content in the mixed gas. The CRN reaction of Al2O3 became more retarded with increasing content of CO in the mixed gas.